1. Field of the Invention
The present invention relates to a length-adjusting device for a head strap. More particularly, the present invention relates to a length-adjusting device for a head strap of a pair of swimming/diving goggles.
2. Description of the Related Art
A pair of typical swimming/diving goggles includes a buckle mounted to each side of a body of the pair of swimming/diving goggles or to a head strap at a location behind the head of the wearer to allow adjustment of the length of the head strap. FIG. 9 illustrates a pair of swimming/diving goggles using a conventional buckle 1′ to adjust the length of a head strap 3′. The rigid buckle 1′ includes a connecting portion 11′ on an end thereof for connecting with the body 2′ of the pair of swimming/diving goggles. A tying portion 12′ is provided on the other end of the buckle 1′ and includes two posts 121′ and 122′. The head strap 3′ is wound around the posts 121′ and 122′ for fixing the length of the head strap 3′. Adjustment of the length of the head strap 3′ is not easy, as the user has to loosen the head strap 3′ from the posts 121′ and 122′. Further, the buckle 1′ is separate from the body 2′ and thus could not provide an integral appearance. Further, the connecting portion 11′ is liable to disengage from the body 2′ when subjected to external impact. Further, the rigid buckle 1′ is in tight contact with a side of the user's head and thus causes discomfort. FIG. 10 illustrates a buckle for a pair of swimming/diving goggles disclosed in Applicant's U.S. Pat. No. 6,691,378. The buckle comprises a body 4′ having a pressing portion 41′, a clamping portion 42′, and a connecting portion 43′ connecting the pressing portion 41′ with the clamping portion 42′.
The pressing portion 41′ includes a post 411′ and a release section 412′ on an end thereof. An end of the clamping portion 42′ includes a clamping hole 421′ through which a head strap 5′ extends. A retaining edge 422′ is formed on a top edge of each lateral wall delimiting the clamping hole 421′ for retaining the head strap 5′.
In assembly, the connecting portion 43′ is wound around a body 6′ of the pair of swimming/diving goggles, with the pressing portion 41′ pressing against an outer side of the body 6′. An end of the head strap 5′ is extended through the clamping hole 421′ and wound around the post 411′ and then extended out of the body 6′ via the clamping hole 421′. The distal end of the head strap 5′ can be pulled until the required tightness and length of the head strap 5′ are obtained, as shown in FIG. 11.
Referring to FIG. 12, when loosening the head strap 5′, the pressing portion 41′ is moved until the post 411′ is disengaged from the retaining edge 422′. An inner portion 52′ of the head strap 5′ can be moved to loosen the head strap 5′.
Although the buckle of FIGS. 10-12 allows easy adjustment and provides stable clamping, the buckle body 4′ is separate from the body 6′ of the pair of swimming/diving goggles and thus could not provide an integral appearance. Further, the inner side of the clamping portion 42′ of the buckle body 4′ is in tight contact with a side of the user's head and thus causes discomfort.
FIGS. 13-15 illustrate a pair of swimming/diving goggles disclosed in U.S. Pat. No. 6,446,272. The pair of dimming/diving goggles comprises a pair of lens parts 71′, a pair of lens frames 72′, two separate buckle assemblies, and an elastic strap 75′. Each buckle assembly includes a buckle body 73′ having a strap-supporting portion 731′ around which the strap 75′ is wrapped, and a slider 74′ which is slidable between a first position (see FIG. 14) and a second position (see FIG. 15) with respect to the strap-supporting portion 731′. When the slider 74′ is moved toward the buckle body 73′, a strap-pressing piece 741′ of the slider 74′ presses against the strap 75′, and an end 742′ of the strap-pressing piece 741′ is engaged with a transverse ridge 751′ on the strap 75′, as shown in FIG. 14. On the other hand, when the slider 74′ is moved away from the buckle body 73′, the strap-pressing piece 741′ no longer presses the strap 75′ and thus allows adjustment to the length of the strap 75′, as shown in FIG. 15.
The strap 75′ is fixed by moving the slider 74′ inward. However, when an excessive pulling force is applied to the strap 75′, the slider 74′ slides and thus could not provide a reliable pressing/positioning effect to the strap 75′. Further, the buckle body 73′ and the slider 74′ are separate from each other and have to be coupled with the lens parts 71′ and lens frames 72′, resulting in troublesome assembly. Further, the assembled buckle body 73′ and slider 74′ may be disengaged from the lens parts 71′ and lens frames 72′ when subjected to impact.
FIG. 16 illustrates a pair of swimming/diving goggles disclosed in Taiwan Utility Model Publication No. M263132. The pair of swimming/diving goggles includes two separate buckle members 81′ and 82′ for coupling with a body 83′ of the pair of swimming/diving goggles. The buckle member 82′ includes a transverse rod 821′ around which a head strap 84′ is wound. The buckle member 81′ includes a resilient piece 811′ and a positioning block 812′ that can be biased by the resilient piece 811′ to press against the head strap 84′ at an end. The positioning block 812′ can be pressed to disengage from the head strap 84′ for adjusting the length of the head strap 84′.
However, the head strap 84′ could not be reliably positioned when the resilient piece 81″ fatigues. Further, troublesome assembling is required, as there are many elements involved. Further, the buckle members 81′ and 82′ are separate from the body 83′ of the pair of swimming/diving goggles and thus could be disengaged from the body 83′ when subjected to impact.